{"product_id":"abb-rex521-feeder-protection-relay-medium-voltage-ied","title":"ABB REX521 Feeder Protection Relay Medium Voltage IED","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003ch3\u003e\u003cstrong\u003eOverview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eABB REX521\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eis a high-performance Feeder Protection Relay engineered for medium-voltage distribution networks and large three-phase AC motor drives. It integrates protection, monitoring, control, and measurement functions in a single Intelligent Electronic Device (IED). The relay is adaptable for a wide range of applications, including incoming\/outgoing feeders, motor feeders, and transformer backup protection. Multiple hardware versions support conventional CT\/VT inputs or modern current and voltage sensors, making it suitable for both legacy and modern substations.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features and Capabilities\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eMulti-functional protection for feeders and large AC motors, including short-circuit, overcurrent, earth-fault, and thermal overload protection\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eDirectional and non-directional protection schemes with three-stage settings\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eStart-up supervision, stall protection, and thermal tracking for motor drives\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003ePower quality monitoring, including total harmonic distortion (THD) and waveform analysis\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIntegrated self-diagnostics, condition monitoring, and event\/fault recording\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eRemote and local circuit-breaker control with multi-shot auto-reclosing\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eConnectivity and Interface\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eSupports Modbus (RTU\/ASCII), IEC 60870-5-103, SPA, and LON protocols\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eTypical I\/O: 9 digital inputs, 4 heavy-duty power outputs, 2 signal outputs, 1 internal fault relay\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eLCD display with user-configurable navigation and alarm indicators\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCompact and robust design suitable for harsh environments (-40°C to +70°C)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eTechnical Specifications\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003cth align=\"left\"\u003eFeature\u003c\/th\u003e\n\u003cth align=\"left\"\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eRated Frequency\u003c\/td\u003e\n\u003ctd align=\"left\"\u003e50\/60 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eAuxiliary Voltage\u003c\/td\u003e\n\u003ctd align=\"left\"\u003e24\/48\/60 V DC or 110\/120\/220\/240 V AC\/DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eDigital Inputs\u003c\/td\u003e\n\u003ctd align=\"left\"\u003e9 (DI9 for time synchronization)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eDigital Outputs\u003c\/td\u003e\n\u003ctd align=\"left\"\u003e4 Power, 2 Signal, 1 Internal Fault Relay\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eCommunication Ports\u003c\/td\u003e\n\u003ctd align=\"left\"\u003eRS-485, RS-232, optional Fiber Optic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eEnvironmental Range\u003c\/td\u003e\n\u003ctd align=\"left\"\u003e-40°C to +70°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eStandards Compliance\u003c\/td\u003e\n\u003ctd align=\"left\"\u003eIEC 60255, IEC 61850 (via gateway)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003eDimensions\u003c\/td\u003e\n\u003ctd align=\"left\"\u003eWidth: 160 mm, Height: 250 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003e\u003cstrong\u003eApplication Scenarios\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003eRadial distribution networks with isolated, resonant, or solidly earthed configurations\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMotor protection in circuit breaker-controlled medium and large AC drives\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eBackup protection for power transformers and high-voltage line relays\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFAQ\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can the REX521 support modern sensor inputs?\u003c\/strong\u003e\u003cbr\u003eA: Yes, specialized versions support current and voltage sensors such as Rogowski coils, in addition to conventional CT\/VT inputs.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Is the relay suitable for outdoor or harsh environments?\u003c\/strong\u003e\u003cbr\u003eA: Yes, the unit operates reliably in temperatures from -40°C to +70°C.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can it integrate with SCADA systems?\u003c\/strong\u003e\u003cbr\u003eA: Yes, it supports multiple industrial protocols including Modbus and IEC 60870-5-103 for seamless substation automation integration.\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"ABB","offers":[{"title":"Default Title","offer_id":44121690079331,"sku":"REX521","price":180.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0549\/2775\/3315\/files\/ABBREX521.jpg?v=1776388094","url":"https:\/\/precisemodule.com\/products\/abb-rex521-feeder-protection-relay-medium-voltage-ied","provider":"Precise Module Ltd.","version":"1.0","type":"link"}